Visualize the sugar

We've written easily half a dozen reports on different research articles focusing on the effects of drinking sugar-sweetened beverages on your weight and your kids' weight as well as contributing to high blood pressure, poorer cholesterol scores, diabetes, gout, and kidney disease.

As you probably know, a number of different approaches have been proposed to try to affect how much of these sugary drinks people consume, from limiting the size of beverages people can purchase (New York) to taxing the sugar content of the beverage (recently proposed in San Francisco). A group of researchers at the University of Alabama theorized that showing people concrete representations of the amount of sugar in a drink might deter people from drinking it - and devised a series of four interconnected studies to find out if that might not be the case (Appetite 2014;83:10-18).

They initially noted that the sugar content of a beverage is noted in the Nutrition Facts in grams per serving. In their first study they set up a table in a university common area and invited passersby to participate in what they called their "estimation study." Each person was shown a 20-ounce bottle of Pepsi and informed that the bottle contained 69 grams of sugar. They were then asked to move 69 grams of sugar from a 2-pound bag of sugar into a smaller container. Half of the participants were given no further information, while the other half, in order to help them visualize the amount, were told that 2.5 grams of sugar was the size of a sugar cube. On average, those without the extra information mis-estimated the volume of sugar by 50 grams - while those with the extra information only mis-estimated by an average of 9 grams. Clearly, the researchers concluded, most people are not able to accurately visualize the amount of sugar represented by the number in the Nutrition Facts.

In their second study, the researchers surveyed 74 people anonymously. First the participants were asked how often they usually drank 4 different sugar-sweetened beverages: Coke, Sprite, Mountain Dew, and Dr. Pepper (those who did not drink sugar-sweetened beverages at all had been excluded from the study). Then, for each of the four beverages, they were shown an image of the beverage and asked if the image made the beverage LESS or MORE attractive to drink, on a scale ranging from 1 (much less) to 5 (much more). Each image of the beverages was randomly chosen from the following: the beverage without any special labels, the beverage plus a label stating the amount of sugar it contained in grams, or a pyramid of sugar cubes in an amount corresponding to the amount of sugar the beverage contained. Afterwards they were asked how often they intended to drink the 4 different sugar-sweetened beverages. Those participants who were the pyramid of sugar cubes reported being less likely to want to drink the sugar-sweetened beverages when the amount of sugar was presented in writing, and FAR less likely to want to drink them when the amount of sugar was presented in terms of sugar cubes.

In a natural corollary to experiment 2, over 100 passing college students were offered a free beverage for completing a survey. Several different sugar-sweetened and unsweetened beverages, including water, were displayed on two tables. On one table, each sugar-sweetened beverage was displayed next to a pyramid of sugar cubes illustrating the amount of sugar in each beverage. On the other table, a prominent label specified the number of grams of sugar contained in each beverage. Half the students were directed to select their beverage from one table and half from the other. Those who were directed to the table with the numeric labels (not the sugar cubes) were almost 3 times more likely to choose a sugar-sweetened beverage for themselves than those whose beverage was illustrated with a pyramid of sugar cubes.

In the fourth and final experiment, the researchers asked over 100 undergraduates to participate in a "learning by estimation" study. They were asked to estimate various amounts by converting one unit of measure into another, including currency, weight, volume, and distance. For half of these participants, questions were included on converting grams of sugar into the approximate number of sugar cubes (~5 grams of sugar = 2 sugar cubes). At the close of the experiment the participants were asked to choose a reward. The reward options were presented in a list that included several sugar-sweetened beverages, labeled with the amount of sugar they contained, as well as water. Before choosing their reward, however, half of the participants were given a "health message" that excess sugar consumption was associated with obesity, type 2 diabetes, and heart disease. Those who had both learned how to convert grams of sugar into sugar cubes AND were shown a health message about sugar were by far less likely to choose a sugar-sweetened beverage for their reward than those who had not learned to convert grams into cubes - about 30% less likely.

What this means for you

The researchers felt that it was clear that people were not very good at estimating the physical amount of sugar in a beverage, but that when shown the amounts in concrete ways (the sugar cube pyramid) they would find the beverages less attractive. However, with some education people could be taught to visualize the amount of sugar in a beverage (converting grams to cubes), and that might be effective as well. Before you next choose a sugary beverage, take a moment to really think about how much sugar is in that can or bottle.

First posted: October 8, 2014